Distributed Systems Network Management (DSNM) Subsystem Interface Development Guide

I Process Development Process
Distributed Systems Network Management (DSNM) Subsystem Interface Development
Guide—109759 3-5
I Process Program Structure Concepts
Command Context
A command context is a collection of data in memory reserved for a particular thread’s
exclusive use during its execution. When the frame receives a command, it creates an
instance of the command thread and dynamically allocates memory for a command
context area that is preserved for the life of the thread. Thread procedures must use
memory within their context area.
Formatted Object
A formatted object is the data structure, defined by the ZDSN^DDL^FOBJECT^DEF
DDL structure, that defines a subsystem object to DSNM. The fields within the
structure contain information about all the relevant attributes of a subsystem object.
Each object that a command has to act on is defined as a filled-in formatted object
structure.
List
A list is a double-ended queue structure that consists of a list declaration and list
members:
•
The list declaration is a small data structure that holds control information for use by
the I process memory management services. Its size and structure are fixed.
•
A list member is a block of memory, the size and description of which are
determined by the thread. Memory is allocated dynamically as members are added
to a list, and deallocated as members are removed from a list. List members can be
of any size.
Two predefined list structures are available in the thread's command context space:
•
The input object list is the list of objects (each one of which is represented by a
formatted object structure) upon which a DSNM operation is performed.
•
The output object list is produced by the command thread when processing the
command; it is initially empty.
Library functions support creation of additional lists for intermediate data storage.
CI
A CI is a control interface: any gateway to the subsystem that provides control. Within
the I process model, a CI is conceptually the name of a control interface, analogous to a
NonStop Kernel process name. Like a NonStop Kernel process, a CI can be opened for
communication. An open CI is referred to by a ciid, which is the functional
equivalent of a NonStop Kernel file number for an open NonStop Kernel process.
_SEND^CI is an operation that provides for communication with an open CI.